From the Interview:
JO: Has zombie fiction seen its apex? Or is there more that can be done with the archetype?Take that Vampires.
JM: Not even close. Zombies are a very elastic storytelling trope, and as such they may ultimately prove to be better for original storytelling than vampires. Consider, in most recent vampire fiction the monster has been severely humanized. He's charming, romantic, tragic, etc. He's become the character, which may be interesting but it also reduces the fear factor and it switches the focus from the human characters to this immortal charmer. Zombies aren't charming, and they don't have personalities. They're walking corpses with no higher functions. They certainly aren't romantic. What they represent in zombie fiction is a constant and universal threat that is implacable and unbearable. That kind of threat puts all of the characters under pressure, and from a storytelling point of view, characters under pressure are the only interesting ones to write about. Under stress, people change, their behavior becomes warped, their facades crack and fall off, and this allows writers to tell complex stories about real people in dreadful circumstances without having to have them react in any way with the monsters other than the way people would if that threat was a tsunami, a plague, or something equally large and emotionless.